Field of Embodiments
The disclosed embodiments relate generally to a culture vessel and a method of growing cells in a culture vessel.
Description of Related Art
Cell culture is a laboratory process used primarily for the growth, propagation, and production of cells for analysis or the production and harvesting of cell products.
Traditional culture vessels often use flat bottom dishes to grow cells of interest. Flat bottom dishes, such as flasks or Petri dishes or roller bottles, provide a limited surface on which cells can attach and grow.
Other culture vessels use microcarriers to grow cells of interest. Microcarriers increase the volume available on which cells can grow. Microcarriers may be suspended in a growth media in a culture vessel to give the cells on the microcarriers access to oxygen and other nutrients needed for the cell growth. Microcarriers may be stirred or agitated to keep them suspended in the growth media and promote cell growth on their surface. Alternatively, microcarriers and culture medium may contact a chamber placed on a rocking platform where the rocking motion of the platform induces waves in the culture medium, thereby causing oxygen transfer to promote cell growth on the surface of the microcarriers (e.g., a GE Wave system). Or, for example, a packed bed or flow-through reactor system may pump the culture medium so that nutrients required to promote cell growth may be provided to microcarriers located within the packed bed or flow-through reactor system.
Conventional mechanisms used to stir microcarriers and maintain them in suspension include a spinner flask, a tissue culture container, and the incorporation of various geometries in the walls of a rotating element within a bioreactor. A spinner flask may include a culture vessel and a suspended impeller positioned inside the culture vessel. The suspended impeller may be driven by an external rotating magnet positioned under the base of the culture vessel to cause the suspended impeller to rotate within the culture vessel and maintain the microcarriers in suspension. A tissue culture container, for example TPP's tissue culture and centrifuge tube, may allow for culture growth when the tubes are placed in racks and then into an incubator; the tubes may be shaken while in the incubator. The incorporation of veins of various geometries in the walls of a rotating element within a bioreactor is designed for large scale production environments. The incorporation of veins of various geometries in the walls of a rotating element within a bioreactor also requires a fixed stirred element, disassembly for cleaning, and a flow through system. Conventional mechanisms, such as the two previously mentioned, may impart hydrodynamic stress, such as excessive shear or acceleration forces or eddies, on growing cells, that can damage or alter the structure of the growing cells. For more information on shear forces please see the article entitled “Physical Mechanisms of Cell Damage in Microcarrier Cell Culture Bioreactors,” published on Nov. 30, 1987 and herein incorporated by reference.
Conventional mechanisms also may include a magnetic impeller. The magnetic impeller may include a paddle and an integrated magnet. The integrated magnet provides a smooth, even rotation at required speeds on a magnetic stirrer. Magnet microcarriers placed in such conventional mechanisms may get stuck, for example, to the magnetic paddle or be drawn, for example, toward the bottom of the spinner flask where the magnetic stirrer is positioned. This attraction prevents the cells on the magnetic microcarriers from obtaining proper nutrients to grow. Conventional mechanisms, like the magnetic impeller, may also prevent cell separation beads from properly separating single cells suspended in the spinner flask. Separation beads, such as Dynal beads from LIFE technologies or MACS Microbeads from Miltenyi Biotec, are attracted to the magnetic paddle or are drawn toward the bottom of the spinner flask where the magnetic stirrer is positioned, for example, because of the magnetic properties of the separation beads. This attraction prevents the separation beads from properly separating any single cells suspended in the spinner flask.
There is a particular need for stirring and particle dispersing actions to be inherent in a disposable bioreactor tube or vessel, which is currently not addressed. The disposable bioreactor tube or vessel may have enhancements such as sterility for cell culture, specialized closures, and other benefits above and beyond the critical element of stirring. For example, in order for a liquid handling tool, such as a pipette, to access the bottom of the vessel, the stirring elements must be arranged to allow access to the bottom of the tube where the bioreacted material may accumulate. A need exists for an improved technology that addresses issues such as, for example, the disadvantages of the conventional mechanisms noted above.